DE60317541T2 - METHOD FOR DETERMINING A TRANSMITTED PORTAL IN A WIRELESS NETWORK AND CORRESPONDING PORTAL DEVICE - Google Patents

Description

The The invention relates to a method for determining a parent portal in a wireless network, especially if this wireless network is one for with the portals connected devices forms transparent bridge. It also concerns a portal device.

It is known to use multiple wired communication buses interconnect one or more wired or wireless bridges. bridges can Two or more portals comprise each portal with a bus or subnet is connected. In the resulting network everyone can Bus or each subnet remain disconnected (for example, everyone retains Bus its own bus ID), although devices depend on their abilities and their knowledge of the bridges with Devices on other buses or subnets can communicate or Not. Another approach is so-called transparent bridges to use that for certain devices do not or at least certain software layers of these Devices are not visible. For example, it is possible to have two or to interconnect more IEEE 1394 buses using transparent bridges, to a single "virtual" IEEE 1394 bus too produce. With one of the real buses connected devices is made believable that all Devices of the network are present on a single bus.

This approach is developed in 2 patent applications filed by the assignee of the present invention. On December 5, 2002, PCT application published WO02 / 098061 entitled "Method for managing a wireless network with more than two wireless devices" describes the architecture, association, and reset operation and connection establishment in a network with transparent bridges. On November 7, 2002, PCT application published WO02 / 089421 entitled "Interface Circuit" describes in detail the physical layer used to receive and transmit reset related information used by the bridge portals in this context. Both applications are filed on behalf of Thomson Licensing SA.

Of the arising from the interconnection of buses or subnets under Use of transparent bridges resulting virtual bus or the corresponding network follow the Rules that govern a real bus or network. For example, in the case of IEEE 1394, a virtual bus has a similar one Topology associated with connections Mother and daughter devices used during the reset process. Also allows the total number of devices on the virtual bus in the particular Do not exceed example 63 devices.

The connections of virtual bus devices can be physical ports - the z. For example, a child device physically includes a parent device connect to a real bus, or be virtual - z. B. for the purpose of simulating a single virtual bus two Portals at the wireless bridge connect logically.

The problem is that in order to comply with the rules valid for a real bus or real subnet, the number of ports of a device may be limited, e.g. 16 in the case of the IEEE 1394 bus. As a result, depending on the topology of the portals in the virtual bus, it may not be possible to connect to a new portal if a corresponding "virtual" port on a parent portal is not available. This problem is caused by the 3 illustrated a topology of a network with a first portal device (Portal 1) connected via an IEEE 1394 bus with 15 devices through the same number of physical ports and a transparent with a second portal device via a 16th "virtual" port. If the first portal is a mother device in the sense of e.g. As the IEEE 1394 topology is and if a new portal to connect to the wireless network, there is no way to connect the new portal.

Examples of the prior art in the present technical field are in documents WO 95/12942 . WO 93/07691 and EP0932279 disclosed.

• – Bestimmen für jedes Brückenportal der Anzahl von Anschlüssen, mit denen andere drahtlose Vorrichtungen verbunden werden können;
• – Wählen eines Brückenportals als Mutterportal als Funktion der Anzahl solcher Anschlüsse,
• – Anschließen anderer Brückenportale an das ausgewählte Mutterportal.

The invention relates to a method for parent portal selection in a transparent wireless bridge, said bridge comprising at least two bridge portals, comprising the following steps:

• For each bridge portal, determining the number of ports to which other wireless devices can be connected;
• - choosing a bridge portal as parent portal as a function of the number of such ports,
• - Connecting other bridge portals to the selected parent portal.

According to the invention Topology for selecting a new parent portal on the wireless network changed, this new parent portal based on available virtual connections selected becomes.

To an embodiment The invention is the sum of the number of virtual ports and the Number of physical connections a bridge portal limited to a predefined number, and where the number of virtual connections and physical connections is configurable.

To an embodiment The invention is the chosen one Portal the only portal that does not root at one with this selected Portal can be connected local bus.

To an embodiment of the invention the method further includes the step of initiating the selection of the parent bridge portal after assignment of a new bridge portal.

To an embodiment of the invention the method further comprises the step of checking before initiating the Choice, whether the current parent portal has a free virtual port, and if so, connecting the new portal to this port without triggering the Choice.

To an embodiment of the invention the method further comprises the step of rejecting the connection of a new portals when connecting the new portal one invalid Topology would result.

To an embodiment of the invention the method further comprises the step of storing, at the level of Portal device, of at least one of the following: the cause of failure of a Connection of the portal to the parent portal, the failure of the assignment of the portal to a central control of the wireless bridge, the Failure cause to become the mother portal.

To an embodiment The invention is as a parent portal in an initial configuration of Network selected Portal the portal with the largest number of virtual connections.

Also The invention relates to a bridge portal device to connect to a wireless bridge with a first interface to a wire bus and a second Interface to the wireless bridge, characterized in that Microprocessor means for managing ports on its wireless interface to connect to wireless devices according to those defined for the wire bus Includes topology rules, the microprocessor means being for participation in a parent portal selection process are a function of the availability of free connections to the wireless interfaces of gantry facilities of the bridge.

It Now is a non-limiting embodiment the invention described with the aid of the following drawings, which form an integral part of the present description.

1 schematically illustrates a network with two buses connected to a wireless bridge.

2 shows a partial block diagram of a portal device with a modified PHY layer.

3 is a diagram of a first topology of the network 1 ,

4 is a diagram of the network 3 after adding a portal and choosing a new parent portal.

1 shows two IEEE 1394 buses with IEEE 1394 bus nodes and an intervening wireless bridge. The first IEEE 1394 bus has the reference number 7 , Connected to this bus are a number of IEEE 1394 devices, only a few of which are referenced 1 . 2 . 13 and 14 are shown. Such devices may be consumer electronic devices such as televisions, video recorders, camcorders, set top boxes, DVD players, etc., or a computing device such as a PC, notebook, etc. Each of these devices is a standard compliant IEEE 1394 device and has a corresponding IEEE 1394 interface 10 ,

With the reference number 3 becomes a first transmitter / receiver box for the wireless bridge or connection 9 designated. This box, also referred to as a "portal", must have an IEEE 1394 interface, since it also works with the 1394 bus lines 7 connected is. The corresponding interface points in the 1 the reference number 11 on. This interface is different from that of devices such as the devices 1 and 2 , The IEEE 1394 interface 11 has additional features as described below. The portal 3 still has another interface 12 for wireless transmission on. There are already wireless protocols that support high-speed communication. In the present embodiment, the Hiperlan system is used, but the invention is not limited to this context. Broadband Radio Access Networks (BRAN); Hiperlan Type 2; Packet based convergence layer; Part 3; IEEE 1394 Service Specific Convergence Sublayer (SSCS) is an IEEE 1394 data link layer Defined via a wireless network ETSI BRAN Hiperlan 2 emulating underlayer. Other examples of wireless communication protocols for The wireless range are the IEEE 802.11 specifications and the Bluetooth specification.

It It should be noted that a "portal" is also a freestanding one wireless device that can not be connected to other subnets such as an IEEE 1394 bus.

In the 1 is another group of IEEE 1394 devices with their own IEEE 1394 bus 8th shown. There are two IEEE 1394 devices 4 and 5 with standard IEEE 1394 interfaces 10 shown. Also is a second box 6 for the wireless bridge 9 by bus 8th connected. It is necessary that the total amount of bus stations in both groups together including the wireless transceiver boxes 3 and 6 less than 63 is. The reason is that with the wireless bridge 9 both groups are fused together and data communication between devices of different groups from the IEEE 1394 device's point of view does not differ in any way from communication between devices in a group. Thus, at least some of the rules applicable to a single group also apply to the entire network, which may be called a "virtual" IEEE 1394 bus or group. The maximum allowed number of bus nodes in an IEEE 1394 group is 63.

2 shows a build one in each portal 3 . 6 or 15 integrated IEEE 1394 interface 10 , The IEEE 1394 interface is divided into two parts: a section of the physical layer 21 and a portion of the link layer 20 , Both can be integrated on a single chip or two separate chips. In essence, it would also be possible for the link layer portion to be implemented in software executing on a microcontroller. The modified IEEE 1394 interface 11 sits in the same basic structure. However, it contains a memory 22 for storing ID packet related information used as explained below.

Furthermore, the portals include a microprocessor and memory for carrying out the methods according to the present invention. They also include a stack to Hiperlan 2 ,

To the understanding the amendment of the physical layer chip, it helps first explain, which in the case of a bus reset happens. A bus reset is done every time if an IEEE 1394 node is removed from or connected to the bus becomes. A node can be removed from or connected to the bus without turning off the power. An insertion or removal of a Node is of a certain voltage change on the bus lines accompanied. This is detected by electronic means and triggers the bus reset out. After a bus reset takes place a self-configuration phase for the network instead. While In the self-configuration phase, each node sends its own identity packet to the bus to inform every other node in the network about its existence.

One Self-identification package consists of 64 bits, where the last 32 bits of the Inverse of the first 32 bits. The content of the fields of the self-identification packages is explained in the IEEE 1394 standard. Some of them are explained here. At the beginning of a self-identification package is the physical one Identification number of the node. This field is a length of 6 bits corresponding to the numbers 0 ... 63. At the end of the self-identification packages there are 2-bit fields for the connections P0 to P2 of a node. The two bits not only show the existence of the Connection in the node, but also whether the port is active and with a mother or mother Subscriber device is connected in the bus topology. According to the IEEE 1394 bus standard, a node can be equipped with up to 16 ports. If a node has more than three ports, the state becomes these other connections reported in a second or third self-identification package. The last Bit m in the ID packet indicates whether the node has some more connections or not. The IEEE 1394 bus has data communication in the Half-duplex operating mode possible. Therefore, only one node sends data to the bus and the rest stops listening. Of the Bus will depend on the node in a deterministic way granted by the bus topology (especially if a knot is branch or leaf). The physical Identifier number will be the node in the order of the bus grant starting from assigned to zero. To address a data packet is not only the physical identification number (node ID) is used. Every bus also has a bus ID that takes into account when addressing must become.

In the case of in 1 During bus configuration, a number of problems occur during self-configuration following a bus reset. The devices have no knowledge of the wireless link in the network. The bridge causes a bus reset separation. The ID packets must be routed from one group to another over the wireless link.

As an example, it is considered that on the bus 7 a bus reset happened. The reset will be from all stations 1 . 2 . 3 recognized in the group. After the bus reset, the nodes sequentially send their self-discovery packets. Each node in the group collects the corresponding information on a higher level software layer together, z. For example, at the transaction layer to later generate the correct addresses. Also receives the interface 11 in the portal 3 each ID packet and directs it over the wireless link to the second portal 6 further. Also creates the portal 3 a self-identification packet and sends it to the IEEE 1394 bus 7 , The device works on the first try 3 in predecessor mode and generates a self-discovery packet, ignoring that if the bridge were to be replaced by an IEEE 1394 cable, it would have a different physical identification number.

After collection of all self-identification packages from the group bus is from the portal 3 initiated by software means a bus reset on the bus. The self-identification packets are transmitted again via the group bus. The difference is that when the portal 3 it is the turn to send its ID packet, it not only generates its own ID packet, but also all the ID packets of the nodes in the remote group, with the portal 3 generates the self-identity packets in consideration of the topology that would result if the wireless link were replaced by an IEEE 1394 cable. The following are the ones from the portal 3 Identification packets generated as representation of the nodes on the group bus are called artificial self-identification packets.

Next is a bus reset on the remote bus 8th by software means in the portal device 6 initiated. The portal device 6 has collected all self-identification packets from the group bus and generates the corresponding artificial identity packets in this phase. After this phase, the self-configuration is over and normal data communication can begin or continue.

As As indicated above, an IEEE 1394 node may have up to 16 ports. Since there is no difference between topologically connecting a portal to a node on his local bus physical connection and connecting a portal to another portal via the wireless medium gives virtual connection, are the 16 connections split between real and virtual connections.

A portal, z. B. the first portal of the 1 , can 15 ports attached to IEEE 1394 devices and one at another portal, e.g. B. the portal 2 attached connection. If portal 1 is the top-level portal in comparison to all other portals, no further portal can be connected for integration into the virtual bus.

It has been recognized by the inventors that portals other than the parent portal may have free virtual ports. One of these other portals is then chosen as the parent portal for the other portals in the topology. In the example of 3 the portal has 2 13 free ports. The 4 shows a new topology after connecting a third portal with reference numeral 15 , If, according to the preferred embodiment, a new portal is added to the network, then it should be connected to one of the 'free' ports of the current parent portal. Connected devices then see only a minimal change in the topology (e.g., addition of a new branch), which can minimize bus traffic (devices do not need to re-learn the identity of all attached devices if they have an appropriate node identification method such as that described in U.S. Pat filed on May 21, 1999 patent application EP0961453 to accept the described. If it is not possible to keep the current mother device, but it appears possible to establish a valid topology by choosing a different mother device, then this is done. If it is not possible to determine a valid configuration then the new portal will not be connected and the current configuration will be retained.

The Number of wired and wireless side assigned connections can be fixed or configurable. Even if a large number physical connections to disposal can stand certain of these connections be locked to ports to free up to connect wireless daughter devices. at the current one embodiment it is assumed that the modified PHY is able to handle more than one virtual connection.

To In the preferred embodiment, devices connected to a real connection be and over a virtual terminal to be connected devices have equal priority on a query justice basis.

If a device is connected to a portal device is a connection of this Set to Active - all the way regardless of whether the connected device is an IEEE 1394 device or another portal is. A connection can be a wired one or a wireless device.

According to a variant embodiment, a portal may deactivate a connection with another portal via a virtual connection in order to allow the connection of a device to a real connection. The IEEE 1394 device be then takes priority over a portal. The reverse is not true: a portal can not disconnect a device on the local wire bus to replace it with a portal on a virtual connection. According to the preferred embodiment, the number of ports of each type of device is predetermined, but according to one embodiment, it is variable and may be user-configurable.

in the former case, the number of wire connections and wireless connections is given. The each number may depend on the function that the portal has becomes. If the portal is to be connected to many wire devices, the number of wire connections is increased. If is intended to use the portal as a parent portal in the wireless bridge, The number of wireless connections will be at the expense of the number of real connections elevated.

Should the number of connections be configurable in any way, the user can increase the number of real connections and virtual connections set dynamically.

If the user intends to attach the device to multiple wire devices can connect he / she decides to allocate more connections for this purpose.

Mother Portal node choice

It now the choice of a parent portal is described. The procedure is, unless otherwise indicated, through a portal, preferably the mother portal, executed.

The the following applies if the number of virtual ports on portals differs is. If the number on each portal is the same, the choice must be based on a criterion other than the number of virtual ports.

Of the first case consists of the addition a portal to an existing wireless network.

If the network is added a new portal, then it should one of the 'free' virtual ports of the current Mother portals are connected, unless they are the result resulting topology is considered invalid consider (for example, too many nodes in the resulting Network). Connected devices will then only make a minimal change in topology (i.e., addition of a new branch), whereby the bus traffic can be minimized. If not possible is due to lack of free connections the current parent portal to keep, but it possible appears by choosing to get a valid topology from another parent portal, then this will be done. If it is after consideration of all portals as possible Parent portal (including the new portal) not possible is, a valid configuration The new portal will not be connected and the current configuration will be determined will be maintained.

It now becomes the detailed Method described.

Assignment in the case of connection to an existing network is carried out as follows:
When a new portal to the wireless network is added, an RLC (radio link control layer) allocation process is performed between the central controller of the Hiperlan 2 network and the new portal. Portals can now exchange information; this allows the incoming portal to recognize which of the other portals is currently the parent portal.

Even though assigned to the wireless network in the sense of Hiperlan 2, is the new Portal not yet connected, in the sense that it is in the virtual IEEE 1394 bus topology is integrated. The new portal will be a bus reset performed on his local group (this can be before or after the assignment performed become). Preferably, the portal tries on its local bus to become the root. This can be done by generating multiple bus resets, to try to force the root. According to the preferred embodiment should if a bus reset happens on a bus where the new portal is not the root, the portal only try to become the root if the previous one Root has left the bus. Should be the previous root still on the bus, the portal does not try to root. This is not necessary because the node that is root is likely would prevent the portal from To become root. This avoids bus reset turbulence.

The new portal submitted then to the present Parent portal accurate information about his abilities (eg the number of virtual connections, which can be implemented by him), and the local configuration (Topology data including the number of devices connected to its local bus and whether it has become the root or not).

from current Parent portal processes this information along with information which holds it as to the current configuration of the rest of the network.

When the new portal root on his bus is and the current parent portal has a free virtual port available to connect it and does not exceed the resulting number of devices 63, then the portal is connected and the network will perform true resets to create the new topology. According to one embodiment, the section count may be the new configuration 16 do not exceed.

Should exceed the resulting number of devices 63, the new Portal not connected and the current parent portal remains. A bus reset procedure is not necessary then. If a reset is still performed, try the current one Mother portal, mother portal to stay.

If the new portal is not the root of his bus and there are enough skills (in terms of available Connections) has, checks the current parent portal, if it is even root on his bus. If so, then the new portal becomes the parent portal. Unless, then it will be from the present parent portal a bus reset method initiated to become root. If it does not succeed, will the new portal is not connected.

If the current one Mother portal not enough virtual connections and if another portal (including the newcomer) a sufficient number virtual connections owns, will check if this Portal can become the parent portal. When all portals take root their respective local bus or there is a single portal that there is no root, and this portal has enough capabilities, it should to become the new parent portal. If this is not the case (ie. H. the current one Mother portal can not become the root), then the new portal not connected.

Around a proper reset propagation to admit, there is at most a portal that is not a root on its bus and if it is such portal, then it is necessarily the parent portal.

The rest of the joining procedure follows the PCT application mentioned in the introduction WO02 / 098061 described method.

Of the second case concerns the occurrence of a bus reset.

If the mother portal is the root and on a bus where the daughter portal loses its root state, a bus reset occurs, is the Rule that Daughter portal to the new parent portal will, if there is a sufficient number of virtual connections having.

If the mother portal is not the root and on a bus where the daughter portal loses its root state, a bus reset occurs, then becomes the daughter portal separated.

If the parent portal is the root and on more than one bus at the same time Time bus resets occur and cause root-state loss for multiple daughter portals, one of the daughter portals will be chosen as the new parent portal if it a sufficient one Number of virtual ports having. The other daughter portals are separated.

If the mother portal is not the root and on more than one bus Bus resets at the same time occur and cause root-state loss for multiple daughter portals, these daughter portals are separated.

Of the third case concerns the initial configuration of the wireless network.

If a wireless network initially There is no current parent portal. According to the preferred embodiment Here a distributed procedure is proposed.

A another possibility would it be, the same procedure as for to use the first case described, but the current parent portal through the 'most capable' portal as below defined to replace.

If a new wireless network is being set up (in a similar way as when new portal to the network) becomes an RLC assignment procedure to the central control in the above-mentioned patent application. Portals can then Exchange information.

From All portals will have a bus reset in carried out by their local group. This can be done before or after the assignment. Every portal tries to become the root of his local bus, if they have not yet are. Each assigned portal transmitted then to all other associated portals information about his Skills (that is, the number of virtual ports implemented by it can be) and over the local Configuration (topology data including devices and whether it has become the root or not).

From Each portal processes the collected information.

The 'most capable' portal is defined as the one that supports the highest number of virtual ports. If multiple ports support the same number, one method is common to all Portals allow one to agree on the ranking and the selection of a same portal as the most capable portal, such as: B. using a unique identifier built into the boxes, and selecting among the candidates of the portal with the highest backward identifier.

If only a single portal is not root, it becomes the parent portal become.

If several portals are not root, the most capable one should become the parent portal.

If all portals are root, the most capable one is to become the parent portal.

The Mutterportal decides which other portals it will connect to its wireless connections followed. It does so by observing the restriction regarding itself resulting number of devices (must not exceed 63). According to the above mentioned variant can also be the condition that the section counting the new configuration 16 must not be exceeded become.

Of the Rest of the connection procedure follows that in the above mentioned Patent application described method.

To the preferred embodiment is proposed in every portal (eg using a Register in the configuration ROM structure by definition IEEE P1212) store information that contains local information about the Result of the last configuration / assignment procedure from the View of each portal included. The encoding of this information store is standardized between portals, so that a device with a true application on the wire bus is able to provide this information to read and the user about Failure causes a configuration to inform.

The Message to the user may consist, for example, of the following: "This portal had none sufficient number of virtual ports to connect to all other portals ", or "this portal did not become the root and was not connected "or" the portal failed in the assignment ".

According to one variant includes a Portal a second store that provides global information about the Result of the last configuration / assignment procedure from the View of the mother portal contains. This information store is to be written by exchanging RLC messages, since the information exchange also between the mother portal and all portals possible should not be connected. This information store is only used by a portal if it is the parent portal is. As before, it can be achieved by a proper application of a device to provide feedback on the Users are read.

Even though the embodiment on IEEE 1394 buses connected by a wireless Hiperlan 2 network based on the invention, the invention can easily be adapted to other buses, Subnets and bridge media customized become.

Claims (11)

Mother portal selection procedure under bridge portals in a transparent wireless bridge ( 9 ), whereby this bridge has at least two bridge portals ( 3 . 6 . 15 A portal comprising a wireless interface and an interface to a wire bus, the method comprising the steps of: determining for each bridge portal 3 . 6 . 15 ) the number of ports to which other wireless devices can be connected; - Choosing a bridge portal ( 6 ) as a parent portal as a function of the number of such connections, - connecting other bridge portals ( 3 . 15 ) to the ports of the selected parent portal ( 6 ). The method of claim 1, wherein the sum of the number of connections at the wireless interface of a bridge portal, hereafter called virtual connections, and the number of physical ports of a bridge portal limited to a predefined number on the wire bus interface is and where the respective number of virtual ports and physical connections is configurable. The method of claim 1 or 2, wherein the selected portal the only portal is the root of a portal chosen with this connected local bus or not. A method according to any one of the preceding claims, further with the step of triggering the Choice of the Mother Bridge portal after assignment of a new bridge portal. The method of claim 4, further comprising the step of checking Trigger the choice of whether the present Parent portal has a free virtual connection and, if so, connect the new portal with this connection without triggering the choice. The method of any one of the preceding claims, further comprising the steps of rejecting the connection of a new portal if the connection of the new portal is invalid Topology would result. A method according to any one of the preceding claims, further with the step of storing, at the level of a portal device, of at least one of the following: the cause of failure of a connection of the portal to the mother portal, failure of assignment of the Portals to a central control of the wireless bridge, the Failure cause to become the mother portal. Process according to claims 1 to 7, wherein the Mother portal selected Portal the portal with the largest number of virtual connections is. Method according to one of claims 1 to 8, wherein a physical Connection to connect to a device on a wire bus available connection. Bridge portal device ( 3 . 6 . 15 ) for connecting to a wireless bridge ( 9 ) with a first interface ( 11 ) to a wire bus ( 7 . 8th ) and a second interface ( 12 ) to the wireless bridge ( 9 ), further comprising microprocessor means for managing ports on its wireless interface ( 12 ) for connection to wireless devices according to the wire bus ( 7 . 8th ) defined topology rules, the microprocessor means being suitable for participation in a parent portal selection procedure under bridge portals, which is a function of the availability of free ports at the wireless interfaces of portal devices ( 3 . 6 . 15 ) the bridge ( 9 ). Bridge portal device according to claim 10, wherein the mother portal selection method performed by the microprocessor means as a mother portal for the wireless network selects the portal with the largest number of virtual ports.